Mistakes were Made
by Asriel Dreeumurr
Summary: -spoilers- This is based around the Sans fight during the genocide route and why Frisk had such a personality change from the pacifist route.
1. Chapter 1

Hi, this is my first fan fic upload so if it's not very good I'd like to apologize. Also this contains spoilers for the end of undertale so if you don't want to know what happens think of a BLUE STOP SIGN and stop where you are. Also as a side note I know that Frisk/Chara is genderless but i gave them a female pronoun to make things easier, so please don't get upset by it.

She wants to spare? After all she did, she's choosing to spare?! Sans felt sick, he had just watched this child kill hundreds of innocent monsters, watched her kill his brother, and she asks for mercy?

"*Kid…. GET DUNKED!"

Sans watched as Frisk was beaten and broken again, how many times has it been now? He doesn't care any more, the only thing left for him to wonder is why? Why did this child that saved them all, lead them all to a happy ending reset the world just to kill them? Was she always this evil? Does she just see them as her toys to play with? It doesn't matter any more…

"..."

Still alive, too broken to move, softly sobbing.

"*Just reset kid, then we can do this song and dance a hundred more times."

"..."

"*Then did you give up? Finally sate that bloodlust?! Happy with the lives you already took! Or are you done because it's not as fun as you thought it would be! Did killing your friends turn out to be a bad time!"

"..."

Sans walked to where Frisk was on the floor, as he reaches down to turn her face and look at her, he realises she's already was no reset…..

"*hahahahahahahahahahahahahahahaha!"

Sans looks up to see another child standing at the edge of the room, clutching and laughing like they heard the best joke ever.

"*Who are you?"

The child continued to laugh, but as it continued it no longer sounded as if it carried mirth but rather held a cold chill that crawled up Sans spine. The kid slowed her laughing, as she did so Sans got a better look at her; her appearance was unsettlingly close to that of Frisk, with only minor differences, but while Frisk used to give an air of kindness this girl…. she gave had an aura of cruelty.

"*Hi Sans, my name Chara. I'd like to thank you"

"*Why…?"

"*Why? Because no matter how hard I tried Frisk held onto hope, no matter who I made her kill she stayed determined. Even after all the piles of dust we made she was convinced she could reset it and stop me."

Sans could feel his heart drop as this "Chara" continued to talk.

"*When we finally got to you she hoped she could get you to help. See, every time we died and reset I would lose a little bit of power over her for a while; the first time she found this out was when we fought Undyne. Heh, i was actually a little worried with her but in the end she wasn't an issue. But you, well you actually got us to the point where I lost control, and Frisk was herself again…. But when she tried to stop the fight and begged for your help, what did you do?"

"I… But… you… she…"

"She has had no control, she was forced to kill all her friends, and when she finally had control again she was brutally beaten to death by one of the only people left that she cared about. That's right you murdered the child that freed you and every other monster, and all you managed to accomplish was break the last of her DETERMINATION, finally letting me take her soul to fix mine."

"*Then why…. why did she reset at all!? If she was really so good why did she reset after giving us a life we could be happy with?!

"*Ooooo, what's this? Looking for a reason to justify your actions? The reason she reset was that not every monster was happy on the surface because of issues they had underground, and Frisk thought if she reset and helped them, then followed the same route as last time she could make everybody happy. Well…. imagine her surprise the first time I took over, and forced her to bash a frog's head in with a stick, or even better when I made her kill that stupid goat, it was beautiful getting to kill the bitch that raised me and listen to Frisk beg me not to do it. I have to admit listening to Frisk beg me not to kill everyone was a lot of fun, but her constant attempts to reset were really annoying. But that's because she didn't know how resets work, whenever someone shows up with more DETERMINATION than the last person with reset they lose the ability. But you already know that don't you Sans, since you could do it before, at least until Asrie- sorry I mean Flowey, arrived and overpowered your ability to reset, then Frisk overpowered Flowey, and I overpowered Frisk."

Sans looked down to Frisk, was she really just trying to make things better but this… abomination took control and forced her to do this? He tried to think back, through all the times he had lived through this world had he ever heard of Chara? He could feel as if somewhere he remembered a warning, but who warned him and what the specifics were he can't remember. Sans looked down at Frisk's broken body and could feel tears welling up.

"*Sorry kid… looks like I messed up…"

"*Yep."

Before he could react he felt a knife cut through his chest knocking him down. There was red seeping from the hole, what it was didn't matter. Sans knew he was dying, so he got up and decided to do the only thing he could do.

"*I'm going to Grillby's'…"

An empty hope to find comfort in place he could never reach… but at least it was something. As Sans looked up he saw his brother looking at him, with a look of expectation.

"*Hey Papyrus, you want anything?"

Sans felt a small hand grab his, when he looked down he saw Frisk holding his hand. Sans realized that even if he died, he wouldn't be alone, so he left with his brother and this small human, even if there is never another reset... they'll be happy.

…

Chara watched as Sans turned to dust, while she was happy that he was finally dead it annoyed her how he was smiling at the end. It doesn't matter she thought, she'll still go and kill her brother and the king, then take the souls. Once she takes the souls she'll find the evacuated monsters and kill them too, then she'll leave and live as a god…. All according to plan.

If people like the story I do plan on writing an extra to this taking place after the end of the genocide route, so let me know what you think, and whether or not i should upload the second part.


	2. Chapter 2

*It's completely silent*

Every echo flower in Waterfall was silent. No wishes, no passing conversations, nothing….

Chara was happily bounding through Waterfall enjoying the silence, slapping the echo flowers as she passed. Chara had already killed Asgore and Flowey, and could have already left, but she had to make the lizard pay. That Alphys had taken all the monsters and hidden them, Chara needed to kill them all if she wanted to prove herself the strongest.

Chara's hunt had lead her back to Waterfall but the trail grew cold, so Chara decided to just enjoy herself while she was here, and her fun was to slap the flowers and listen to the silence.

*Slap!*

*It's completely silent*

*Slap!*

*It's completely silent*

*Slap*

*Are you happy?*

Chara froze for an instant, then she drew her knife and spun looking around in a panic. No one should be left here she was sure she checked here before, she knows no one was left, but who spoke to the flower?

"WHO'S THERE?!"

Silence…

Chara began to get angry, someone was here, but where are they now. In her now frantic search she brushed against another echo flower.

"I asked if you're happy?"

"I SAID WHO'S THERE!"

Chara was beginning to worry, how could an echo flower continue the conversation from before, as if it were directed at her. With a prod she hits another flower.

"Was killing them all worth it?"

"WHO ARE YOU!?"

Without even moving the flowers around Chara begin to speak.

"I am no one worth mentioning"

"WHERE THE HELL ARE YOU!?"

"Don't you know how to meet a new friend…. Turn around and say hello…."

Chara slowly turned to see whoever was speaking through the flowers, when she did turn she saw a tall thin skeleton wearing black robes and a cracked face wearing a permanent smile, and rolling a buttercup flower in his hands.

"WH-WHO ARE YOU!?"

Chara was confused, why were her hands shaking… She can't be scared! HE HASN'T EVEN MOVED YET!

As if reading the mind of Chara the creature begins to flick one of it's hands in sign language. As he flicks his hands the echo flowers begin to speak for him.

"Determination…. Both the strength and weakness of a human soul… But lethal when it comes to monsters…. and humans if they eat it."

Chara froze. He Can't know her secret… no one knew! But… why does he have that buttercup…. he knows.

"Not many know what determination in…. even less know what it does… and where to find it outside the human body, well…. You already know where…."

With this he placed the butter cup in his mouth, leaned back and swallowed.

"For a long time I thought I was the only one to know the secret… I consumed the flowers, then died in the core…. my own creation…. but I did this so I could watch over my children for the rest of time…"

Chara already knew what he was talking about. When she was still a normal human and was being raised by the monsters, she found a lab that belonged to the former royal scientist, in the lab she found a number of notes that were coded. In under a year she deciphered them and learned that the yellow flowers, the buttercups, have determination in them.

This lead Chara to create experiments of her own to test the power of the flowers. At first she experimented on monsters away from prying eyes and learned that their bodies couldn't take the determination, and quickly liquified. How during a test where she "accidently" added the flowers to a pie showed her that BOSS monsters were capable of surviving it intact. This lead her to believe she could survive ingesting the flowers, and make it so her soul would remain here forever… but it still made her sick sicker than she thought she was sure if she got more flower she could make the plan work, but the only ones she could think of in her ill and unfocused state were the ones in the village she came from. But before she could get them her body died and Asriel used Chara's soul to take her to the flowers in an act of kindness. Then when Asriel returned and died holding Chara and a number of butterscotch flowers, his soul began to migrate to the flowers, but even in death Chara wasn't finished taking advantage of her adoptive brother, she took his soul in an attempt to repair her own, leaving only a part of his essence to enter a flower, an empty part that would crave a soul, so that it could be whole again.

Even after stealing the soul Chara couldn't fix herself, she needed a human soul similar to her own if she wanted to return. But during her time as an empty soul watching them she learned of the reset, and she watched six different humans enter the underground; none of these humans lasted long, three killed by the skeleton Sans, one by Undyne and two by Asgore… but none of them ever remembered doing it, like it's just gone.

The skeleton continued to watch as Chara had her internal struggle, unaware that the skeleton knew what she's thinking, but he is a gentleman and knows not to interrupt a lady… no matter how bat shit crazy she is.

Chara finally noticed where she was again and the creature only a few feet away. As she looked at him she couldn't help but feel as if he knew something.

His hands begin to move again, and the flowers began to speak again.

"You wish to know why they don't remember who killed the humans…. I made them forget…"

"H-h-how? No one can do that unless there's a reset, but those deaths happened and should be remembered!"

"A father protects his children…. even if it's from themselves….. I made them forget their crimes so they would remember who they are….."

Chara was scared now, so she did what she did what she always does when she's scared, she attacked. She jumps forwards with her knife drawn and slashes across the chest of the monster… but it passes through, and he continues motioning as if nothing happened, regardless of how many times she tries.

"Of course it's not perfect…. sometimes bits will be remembered…. like with Sans, but I suppose that's my fault….."

"WHY WONT YOU DIE!"

"A monster's body can't survive determination…. But the soul can if the body is destroyed…. and a monster that has consumed the yellow flower and died in the core, gains powers beyond anything imaginable…. like the ReBOOT…."

"What the hell is reboot!?"

"Everything is reset…. the world...even you…."

"What…?"

"You will return to when you arrived here, with no memory of any timeline…. no one will remember anything…. but if helps, no one will remember me either…"

Chara was terrified, she frantically swung and stabbed, she can't be forgotten!

"It's a beautiful night…"

"I won't be FORGOTTEN!"

"The stars are shining…"

"NOOOOOOO!"

"The crickets are humming…"

"NO! NO! NO! No!"

"Children are dreaming…."

"I-I- I don't want to be forgotten…"

"On night's like these…."

"But… I wasn't done playing…"

"You and me…."

"..."

"Should be forgotten…"

He was sure he heard something. Asriel entered the small clearing with the flowers and saw a small girl laying in them.

"Are you okay? What's your name?"

"Chara…"

"Chara huh? That's a nice name, my name is Asriel…"


End file.
